1. Field of the Invention
Manufacturing prismatic ophthalmic lenses with particular reference to improvements in lens chucking apparatus.
2. Description of the Prior Art
The introduction of prism in ophthalmic lens surfacing operations has, heretofore, required that a lens be blocked at the needed prism angle prior to attachment to the surfacing apparatus or that a squarely blocked lens be tilted in a surfacing machine chuck with wedges and the like. Illustrations of the former may be found in U.S. Pat. Nos. 3,118,198; 3,195,197; 3,866,667 and U.S. Pat. No. 3,490,182 illustrates a blocking scheme using spacers of differing thicknesses for prism adjustment.
Considerable tediousness and much wasted time is experienced in conventional prism blocking procedures and/or wedging in chucks for the many different prism settings encountered in the field.
Accordingly, it is an object of the present invention to simplify and accelerate the manufacture of prismatic ophthalmic lenses and, more particularly, to simplify lens blocking and chucking for prism surfacing operations.
Other objects and advantages of the invention will become apparent from the following description.